You know what they call doing a task the same way every time? Micromanagement. Red tape. Waterfall design. In general, a bad thing. Kills creativity, slows everything down, minor setbacks become huge problems because there's no flexibility.

Defining every single step of every single task and making them perfectly repeatable works in an assembly line. But as an office assistant - and doubly so as a personal assistant - it creates inefficiency, makes dealing with edge cases very painful, and greatly increases maintenance burden of keeping all procedures up to date. Instead, giving people some leeway in how they approach their tasks and deliberately underspecifying processes to let them exercise their judgement is shown to work much better. Surely you had it covered in your training materials?